Honing machine for finishing trochoidal bore of rotor housing of rotary engine

ABSTRACT

A honing machine for finishing a trochoidal bore of a rotor housing of a rotary engine. The honing machine includes a honing head and a machine table both of which are driven by a common drive shaft separately from each other in the same direction but with an eccentrically from each other. The eccentricity is adjustable so as to make the honing head follow smoothly and finely the trochoidal inner surface. A clearance control device is also provided in the honing machine, which controls the clearance between the gears intermeshing with each other for transmitting rotation from the drive shaft to the honing head and machine table. A bias pressure control mechanism is also provided which can control the bias pressure or the honing elements of the head against the trochoidal inner periphery in response to the angular positions of the elements relative to the inner periphery. The honing macine may also include a damping device to pneumatically damp or absorb such a shock, if any, as is experienced at the contact interface between the inner periphery and the honing elements.

nite States Patent [191 Dojyo et al.

[ Dec. 3, 1 974 1 I'IONING MACHINE FOR FINISHING TROCHOIDAL BORE OFROTOR HOUSING OF ROTARY ENGINE [75] Inventors: Satoshi Dojyo; TsutomuYoshino,

' both of Hiroshima, Japan [73] Assignee: Toyo Kogyo Co., Ltd.,Hiroshima-ken, Japan [22] Filed: Dec. 27, 1972 [21] App]. No.: 319,000

[52] US. Cl 51/34 J, 51/50 R, 5l/DIG. 32 [51]v Int. Cl E24b 19/08 {58]Field of Search..... 51/50 R, 50 PC, 34 H, 34 J,

'51/353, 349, DIG. 32

[56] References Cited UNITED STATES PATENTS 1,412,867 4/1922 Hill 51/882,263,878 11/1941 Johnson 51/34J 2,813,383 11/1957 La .leunesse....51/349 2,836,936 6/1958 Lovely 51/50 R FOREIGN PATENTS OR APPLICATIONS957,922 0/1964 Great Britain 51/DIG. 1

Primary Examiner-Al Lawrence Smith Assistant Examiner-Robert C. WatsonAttorney, Agent, or Firm--Stevens, Davis, Miller 81. Mosher 5 7 ABSTRACTA honing machine for finishing a trochoidal boreof a rotor housing of arotary engine. The honing machine includes a honing head and a machinetable both of which are driven by a common drive shaft separately fromeach other in the same direction but with an eccentrically from eachother. The eccentricity is adjustable so as to make the honing headfollow smoothly and finely the trochoidal inner surface. A clearancecontrol device is also provided in the honing machine. which controlsthe clearance between the gears intermeshing with each other fortransmitting rotation from the drive shaft to the honing head andmachine table.

. A bias pressure control mechanism is also provided which can controlthe bias pressure or the honing ele* ments of the head against thetrochoidal inner periphery in response to the angular positions of theele- .ments relative to the inner periphery. The honing macine may alsoinclude a damping device to pneumatically damp or absorb such a shock,if any, as is experienced at the contact interface between the innerperiphery and the honing elements.

I T 6 Claims, 8 Drawing Figures HONING MACHINE FOR FINISHING TROCIIOIDALBORE OF ROTOR HOUSING OF ROTARY ENGINE The present invention relatesgenerally to improvements in a finishing machine, and, moreparticularly, to a honing machine for finishing a trochoidal bore of aworkpiece by honing the inner wall surface thereof.

One of the prototype honing machines for finishing a trochoidal innersurface of a workpiece is disclosed in Japanese-Pat. Publication No.6436/1965. According to this patent, the honing machine is intended tofinish the two-lobed trochoidal surface of a workpiece such as a rotorhousing of a rotary engine. In the honing machine, a honing head ofgenerally triangular form is provided at its apexes with stone slips,and is received within the trochoidal bore of the rotor housing in amanner to bring the stone slips into sliding contact with the innerperiphery of the trochoidal bore. In order to smoothly follow theperiphery, the honing head is provided with an internal gear whichmeshes with a stationary outer gear disposed in a coaxial relationshipwith the trochoidal bore. In this instance, the tooth ratio of thestationary outer gear to the internal gear of the honing head is usuallypreset at a value of 2:3. A crank mechanism is also provided which hasits axis arranged concentrically with the trochoidal bore. With thiscrank mechanism, the honing head experiences the crank movement, thatis, it rotates on its axis and is subjected to the planetary movementwith a predetermined eccentricity. Thus, the honing head can conduct thetrochoidal movement relative to the workpiece.

In the conventional honing machine, however, the dimensional and specialrelationships of the gear mechanism and the crank mechanism should meetstrictly severe requirements. As a result, correct centering of themechanisms as well as correct production of the parts of the mechanismsis a quite difficult problem. Moremover, the obtainable trochoidal formcan scarcely be varied. It can also be said that the speed of rotationof the honing head is inevitably limited to a relatively low level, witha degraded production performance.

It is, therefore, an object of the present invention to provide a'honingmachine which is free from any of the above drawbacks.

Another object of the invention is to provide a honing machine in whicha crank movement between the honing head and the workpiece is eliminatedto allow a'high speed of rotation of the honing head.

Still another object of the invention is to provide a honing machine inwhich eccentricity between the centers of the honing head and theworkpiece is controlled over a wide range.

A further object is to provide a honing machine in which the biaspressure of the stone slips against the workpiece inner surface isperiodically reduced or increased in response to the angular positionsof the slips relative to the inner surface.

A further object is to provide a honing machine in which the honing headcan pneumatically damp or absorb such a shock, if any, as is experiencedat the contact interface between the workpiece inner surface and thestone slips.

Other objects and advantages of the present invention will now bedescribed with reference to the accompanying drawings, in which:

36 to 38. These stone slips 36 to 38 are biased out- FIG. 4 is a partialsection taken along the line IVIV of FIG. 1; a

FIG. 5 is also a partial section taken along the line V-V of FIG. 1;

FIG. 6 is a diagrammatical view showing the working pressure controlsystem for use in the honing machine ofFIG. 1;

FIG. 7 is a generally cross-sectional view showing a honing head portionfor use with the honing machine of FIG. 1; and

FIG. 8 is a partially cut-away plan view of the honing head portion ofFIG. 7;

Referring now to FIG. 1, a honing machine according to the inventiongenerally includes a main body 61 which bears drive shaft 16 rotatably,preferably, about its vertical axis. This drive shaft 16 is provided atits both ends with two spur gears 17, 18 which are respectively namedthe head drive gear and table drive gear..

For effecting honing of the inner wall surface 10, for instance, of atrochoidal bore of workpiece 11 such as a rotor housing of a rotaryengine, there is provided in the honing machine a honing head 13 whichin turn is provided on its periphery with a plurality of stone slipswardly into sliding contact with the inner wall surface 10. To thehoning head 13 is coaxially secured honinghead shaft 14 which maypreferably be received in cylindrical shaft 23 having its axis arrangedin parallel with the axis of the drive shaft 16. Within this cylindri:cal shaft 23 is axially movable the honing-head shaft 14 so as to bringthe honing head 13 into and out of the trochoidal bore of the workpiece11. However, the honing-head shaft is designed to forcibly rotateintegrally with the cylindrical shaft 23. This cylindrical shaft 23 isprovided with an integral head gear 21 which is of the spur type.Between this head gear 21 and the head drive gear 17 of the drive shaft16 is interposed a first intermediate idle gear 19 which meshes with thesame for transmitting rotational motion from the drive shaft 16 to thehoning head 13 by way of the cylindrical shaft 23 and the honing-headshaft 14.

The workpiece 11 is securely held on a machine table 12 in position in aknown manner. To this machine table 12 is coaxially secured a tableshaft 15 which is provided with an integral spur gear 22 and which hasits axis arranged with an eccentricity e from the axis of thehoning-head shaft 14 but in parallel with the axis of drive shaft 16. Asecond intermediate idle gear 20 is also provided to mesh with the tableshaft gear 22 and with the table drive gear 18 of the drive shaft 16 soas to transmit rotational motion from the drive shaft 16 to the machinetable 12 through the table shaft 15.

With these construction arrangements, the direction of rotation of thehoning head 13 is designed to be identical with that of the machinetable 12. Moreover, the ratio of speed of rotation of the honing head 13to that of the machine table 12 is preset to have a suitable value, forexample, of 2 3. Thus, the honing head 13 can move relative to themachine table 12 in a fashion to draw a desired trochoidal curve so asto finish the inner trochoidal surface of the workpiece 11.

In the present honing machine is also provided headposition controlmeans which includes head-position control cylinder 24 rotatablyconnected to the honinghead shaft 14 through its piston rod 25. Aworking fluid such as oil under pressure is supplied to this controlcylinder 24 so that the piston rod 25 and accordingly the honing-headshaft 14 is moved up and down along the axis thereof. In this way, thehoning head 13 can move between the two axial positions, that is, at itslower position it is in sliding contact with the inner trochoidalsurface of the workpiece 1 1, while at the upper position it is apartfrom the workpiece 11 in stand-by position for the subsequent honingoperation. In order to hold the honing head 13 at this stand-byposition, locking means may preferably be provided which includeslocking cylinder 26 with piston rod 27 acting as a locking arm. Thispiston rod 27 is normally biased by a compression spring 29 toward theaxis of the honinghead shaft 14. At an upper end of the shaft 14 isformed a radial projection 28 which can be in locking engagement withthe extending end of the piston rod 27. As the honing head 13 is liftedby the action of the pressurized oil in the control cylinder 24,therefore, the projection 28 first abuts and subsequently presses theend of the piston rod 27 against the action of the compression spring 29into the locking engagement therewith. The release of this engagementcan be made manually or with use of suitable means.

As shown in the lower left-hand side portion of FIG. 1, the rotationalmotion of the drive shaft 16 is performed by a suitable prime mover suchas a DC motor 30. This DC motor is of the reversible type and isprovided with pulley 31 on its shaft (not numbered). For transmittingthe rotational motion, an endless belt 32 is carried by the pulley 31and a pulley 33 of a reduction gear apparatus 34. Thus, the rotationalmotion of the DC motor 30 reversing back and forth at a predeterminedtime interval is reduced at the apparatus 34 and is transmitted to thedrive shaft 16.

When, in operation, oil under pressure is introduced into the lockingcylinder 26 with its piston rod 27 remaining in locking engagement withthe projection 28, then the piston rod 27 is moved leftwardly of thedrawing against the biasing force of the spring 29 to'thereby releasethe particular locking engagement. In the meantime, the head-positioncontrol cylinder 24 is also supplied with oil under pressure through asuitable oil conduit (not shown), so that the honing head 13 is loweredinto the trochoidal bore of the workpiece 11. It is preferable here thatthe supply of the pressurized oil to the cylinder 24 is so controlled asto cause the head 13 to vertically traverse in the trochoidal bore witha predetermined stroke. For effecting fine honing of the inner wallsurface of the bore, bias-pressure control means is provided in the headproper, and includes bias-pressure control cylinders 39 to 41respectively for the stone slips 36 to 38. The bias pressure of thestone slips 36 to 38 toward the inner trochoidal surface is controlledby supplying oil at a predetermined pressure level to the controlcylinders 39 to 41 from a pressurized liquid source (not shown) throughan oil inlet conduit 35 and oil passage (not shown) in the piston rod 25and the honing-head shaft 14. The detailed explanation of the operationof this bias pressure control will be made hereinafter with reference toFIGS. 5 and 6.

With the honing head 13 being rotated, in this instance, the stone slips36 to 38 continue to hone the inner wall surface 10 until a finishedsurface of desired accuracy or smoothness is obtained. During the honingoperation, the rotation of the head 13 is directed back and forth at apredetermined time interval. At the instant when the completion of thehoning operation is detected in terms of, for example, friction with theinner surface 10, the oil pressure in the control cylinders 39 to 41 isreleased in the opposite direction, namely, through the not-shown oilpassage and the oil inlet conduit 35, so that the stone slips 36 to 38contract radially inwardly with their outer ends spaced from the innersurface 10. After this operation, the honing head 13 is lifted byintroducing oil under pressure into the lower chamber (not numbered) ofthe control cylinder 24 through an oil passage (not shown). As thelifting operation of the head 13 proceeds, the pressure in the lockingcylinder 26 is released to allow the compression spring 29 to push thepiston rod 27 outwardly into the locking engagement with the projection28 of the honing-head shaft 14 for stand-by status for the next honingoperation. This locking operation may be accompanied by deeneergizingthe DC motor 30, thus finishing one cycle of honing operation.

In order to obtain a variety of accurately finished trochoidal bores ofdesired form, eccentricity control means should also be provided in thehoning machine of the present invention, with the prerequisite that theworkpiece 11 is accurately fastened to the machine table 12. For thispurpose, the eccentricity control means should provide smooth andeffective meshing engagements between the spur gears 17 to 22 withoutadversely affecting the eccentricity e between the center 72 of thehoning head 13 and the center of the machine table 12, as best shown inFIG. 2.

Turning now to FIGS. 2 to 4, a head support 59 bearing the honing head13 and the gears 19, 21 is, after its upper annular support portion 60has been rotatably fitted into an upper support bore 62 of the main body61, fastened to the body 61 by suitable means such as a fastening bolt(not shown). On the other hand, a table support 63 is also providedwhich is interposed between guides 64 for guiding the support 63 towardand away from the drive shaft 16. The supporting position of the tablesupport 63, and accordingly the eccentricity e is thus controlled by theeccentricity control means or bolt 65, as is easily understood withreference to FIGS. 1 and 4.

Apart from the eccentricity control as described above, the clearancebetween a pair of gears, such as, the head drive gear 17 and thefirstidle gear 19 is also adjusted to obtain smooth and effectivemeshing engagements between respective pairs of the spur gears 17 to 22,which will be described with respect to FIGS. 1 to 3. More specifically,the lower portion of the drive shaft 16 is born in lower support bore 68of the main body 61 by way of a cylindrical support 67 of a rocking arm66 which in turn bears the second idle gear 20.

With the construction arrangement as above, when it is intended tofinish a desired trochoidal bore of the workpiece 11 by honing the innersurface 10 thereof with use of the present honing machine, the headsupport 59 is secured to the main body 61 by a suitable fastening bolt(not shown), such that the center 72 of the honing head 13 correctly lison line 71 which is common to the center 69 of the drive shaft 16 and tothe justed by turning the control bolt 65 so as to control thesupporting position of the machine table 12. After completion of thiseccentricity control operation, the machine table 12 is firmly securedto the main body 61 by fastening a T-shaped thrust block 74 mounted inT- shaped groove 73 which runs in the direction of guidance of the table12. The clearance between the gears 18, 22 of the table side and thesecond idle gear 20 is, on the other hand, adjusted by turning clearancecontrol worm 76 and by the following turning of worm gear 77, the latterbeing integral with the rocking arm 66, as best shown in FIG. 3. Thus,the idle gear 20 is held at an adjusted position together with the wormgear 77 by the action of fastening bolt 79 which is screwed into themain body 61 through arcuate slit 78 formed in the worm gear 77, asshown.

The accurate positioning of the workpiece 11 on the machine table 12 canbe carried out in the conventional manner. For this purpose, forexample, a suitable number of positioning pins 80 may be formed on thetable 12 and are fitted into corresponding positioning bores formed inthe lower surface of the workpiece 11.

In the discussion made hereinbefore, the workpiece to be honed is not soexplicitly specified, but the present honing machine is originallyintended to be applied to the finishing of a two-lobed rotor housing ofa rotary engine having its exhaust port formed on the inner peripherythereof. The exhaust port as indicated at numeral 42 in FIG. 6 isrelatively large, so that if the nominal bias pressure toward the innertrochoidal surface should be preset uniform throughout that surfaceincluding the exhaust port 42, the innermost periphery of the port 42would be damaged or excessively finished to invite undesirable engineperformance degradation due to premature leakage of combustion gasesthrough the excessively finished portion. In order to be free from thislocally excessive finishing, therefore, net bias pressure to be appliedto a unit area of the inner surface 10 should be constant even at thereduced-area portion with the exhaust port 42. In other words, thenominal or total bias pressure should be reduced at the reduced-area inan amount to correspond to the reduction in the effective area.

Referring to FIGS. 1, 5 and 6, there is also provided in the honingmachine of the invention detecting means which is responsive to therotational motion of the honing head 13 relative to the machine table 12so as to detect the angular position of the exhaust port 42. Thisdetection is performed in terms of the angular positions of the stoneslips 36 to 38 relative to the two-lobed inner wall 10 of the workpiece11. The detecting means includes detecting gear 43 which may beconnected to any of the gears 17 to 22 for the detection. But, thedetecting gear 43 is integrally connected to the shaft of the first idlegear 19 and meshes with a follower or driven gear 44, as shown in FIGS.1 and 5. The tooth ratio of the gear 19 to the gear 44 is preset suchthat the latter can rotate at a predetermined speed, for instance, atthe relative speed between the honing head 13 and the table 12, that is,with a speed ratio A to the head 13 (or with a speed ratio 56 to thetable 12). The driven gear 44 is secured to a shaft 45, the other end ofwhich is inserted into cylindrical shaft 47 provided with an integraldisc 46. In the shaft 45 is formed a bore 48 into which a lock pin 49integral with the cylindrical shaft 47 is fitted to effect a jointbetween the two shafts 45 and 47. At a suitable peripheral position ofthe disc 46 is provided dogs 50, 51 which are spaced at a distance fromeach other in the axial direction of the shaft 45. These dogs 50, 51together with the disc 46 can move axially of the shaft 45 by theassociated actions of both a change-over cylinder 52 and a compressionspring 53.

Turning especially to FIG. 6, the honing head 13 is, in this instance,of generally triangular shape having its stone slips 36 to 38 arrangedat its apexes apart from each other by an angle of degrees. Accordingly,change-over valves 54 to 56 for controlling the biaspressure controlcylinders 39 to 41 are also angularly spaced from each other by 120degrees around the dogs 50 and 51. The change-over valves 54 to 56 are,as shown, provided between the bias-pressure control cylinders 39 to 41and a pressurized liquid source (not shown), and are responsive to thedetected relative angular positions of the respective stone slips 36 to38 so as to change the respective communications of the fluid sourcewith the control valves 39 to 41. By the changeover operations of thevalves 54 to 56 associated with the rotating dogs 51, 52, the workingliquid or oil under a regulated pressure is introduced from thenot-shown liquid source into the control valves 39 to 41 through an oilinlet conduit 57. The above change-over operations are in synchronismwith the relative rotation of the honing head 13, so that the biaspressure against the inner surface 10 of the workpiece 11 is controlledto be uniform in its net level even when one of the slips 36 to 33passes on the exhaust port 42. The oil in the control valves 39 to 41 isalso periodically released by way of an oil outlet conduit 58. Thedescription of the inside construction of the honing head 13 and thecontrol cylinders 39 to 41 will be made in more detail with reference toFIGS. 7 and 8.

Although the bias-pressure control cylinders 39 to 41 and thechange-over valves 54 to 56 are schematically shown in FIG. 6, theinteractions will now. be described in the following manner. The valves54 to 56 are the socalled two-position valves which are normally biasedradially inwardly by suitable biasing means such as a compression spring(not numbered) and which have an acting rod (not numbered) extendingradially inwardly to be engageable with either of the dogs 50, 51. The

outer ends of the dogs 50, 51 are inclined with respect to thecircumference thereof, such that the inclined ends have a negativeattack angle toward the acting rod. Thus, when the disc 46 rotates inthe direction of the solid arrow, the axial displacement of the disc 46takes place to have the dog 50 engage with the acting rod. When thevalve 56 is moved radially outwardly against the action of thecompression spring, as easily understood from FIG. 6, then oil passagesin the valves shift from the outer block to the inner block. At thisinstant, the control cylinder 41 is supplied with the oil under theregulated pressure through the oil conduit 57. The oil is thenintroduced into the outer chamber (not numbered) of the cylinder 41 tomove its piston (not numbered) radially inwardly together with the stoneslip 38, thereby reducing the bias pressure against the workpiece innerwall by a predetermined amount. As a result, the bias pressure controlis periodically effected when the stone slips 36 to 38 are in slidingcontact with the inner wall portion formed with the exhaust port. Thiswill be understood by referring to FIG. 6, in which the stone slip 38 isapproaching the exhaust port 42 when the acting rod is just prior toabutment with the dog 51. This interaction of the changeover valve 56with the control cylinder 41 is also applied to the pair of the valve 54and cylinder 39, and to the pair of the valve 55 and cylinder 40, in thesequence of rotation of the disc 46.

As has been described before, the rotation of the DC motor 30 andaccordingly of the disc 46 and honing head 13 changes its direction at apredetermined time interval. Therefore, in the case when the disc 46rotates in the direction of the dotted arrow, the axial position of thedisc is shifted to have the dog 50 engage with the acting rods of thevalves 54 to 56, maintaining the negative attack angle relationship.Other interactions of the valves and cylinders under consideration aresimilar to those of the case in which the rotation is directed in thesolid arrow, and, as such, the repeated explanation thereof is omittedhere.

Turning now to FIGS. 7 and 8, the honing head to be discussed isslightly modified to have an additional feature, so that the constituentelements thereof will be renumbered. Referring especially to FIG. 7, thehoninghead body 101 is designed to be vertically moved by such asuitable elevating apparatus (not shown) as described previously. Onthis body 101 is rotatably born through bearings 103 a spindle 102 whichis supplied with rotational motion from a gear or pulley 104 securedthereto. Into this hollow spindle 102 is rotatably inserted ahoning-head proper 106, with a bearing 105 interposed inbetween. Intothe upper end of the head proper 106 is screwed a vibration rod 107which is vertically vibrated by suitable vibration means (not shown).With these arrangements the vertical vibrations are applied to the headproper 106 by way of the vibration rod 107 when in the honing operationof the honing machine. The head proper 106 is formed at its center witha cylindrical oil-pressure chamber 108 which communicates at its lowerend with the biaspressure control cylinders 109 equi-angularly spacedfrom each other and having their axis arranged radially of the headproper 106. In the control cylinders 109, respectively, is slidablyreceived a piston rod 111 which is normally biased radially inwardlytoward the oilpressure chamber 108 by a compression spring 110. Theextending end of the piston rod 111 is provided with a U-shaped slipsupport 112 to which a slip holder 114 carrying the stone slip 113 isswingably connected by means of a rocking pin 115. As better shown inFIG. 8, the stone slip 113 is held in position in an axial groove 117formed between the slip holder 114 and thrust plate 116. The fasteningof the slip 113 is carried out by turning a fastening bolt 118, asshown.

With reference to the upper left-hand corner of FIG. 7, referencenumeral 119 indicates a damping reservoir which stores therein workingfluid or oil under a pressure regulated through air. The dampingreservoir 119 is formed at its upper portion with an air inlet port 124through which pressurized air is introduced into the reservoir 119 froma pressurized-air source such as an air compressor (not shown) via anair conduit 121, change-over valve 122 and air conduit 123 in thatorder. Th upper chamber portion of the reservoir 119 is filled with thethus introduced pressurized air, while the lower portion with thepressurized oil. This oil is to be supplied to the oil-pressure chamber108 from the air outlet port 125 formed at the lower portion of thereservoir 119. The oil passage for communicating the port 125 with thechamber 108 is composed of an oil inlet conduit 126, an oil port 127formed in the head body 101, an oil passage 128 formed in the spindle102, an annular groove 129 in the head proper 106, and an oil passage130 in the head proper 106.

When, in operation, an air intake solenoid 1220 is energized, thechange-over valve 122 is moved downwardly of FIG. 7 to providecommunication between the air conduits 121 and 123. As a result, the oilpressure in the damping reservoir 119 is increased to have apredetermined level. This boosted oil is then introduced into theoil-pressure chamber through the above-described oil passage. With thepressure in the chamber 108 increases, the piston rod 111 is displacedradially outwardly of the head proper 106 against the biasing action ofthe spring 110 to press the stop slip 113 onto the workpiece innerperiphery with a predetermined pressure level. According to apredetermined operational sequence, the air-intakesolenoid 122a isdeenergized with the concurrent energization of an airexhaust solenoid122b. At this particular instant, the change-over valve 122 is lifted torelease the boosted oil pressure in the chamber 108 by way of an airconduit 134.

The energizing operations of the two solenoids 122a, 122b may preferablybe carried out in synchronism with and in response to the relativeangular positions of the stone slips 113 with respect to the machinetable, as is the case in which the honing head under consideration isapplied to the honing machine as has been described in detail withreference to FIGS. 1 to 6. In this way, the bias pressure of the stoneslips 113 against the inner wall surface 10 of the workpiece 11 is alsoreduced by an amount sufficient to prevent excessive honing of theworkpiece portion at which a bore or the exhaust port 42 is formed. atthe instant when one of the slips 113 runs over the port 42, as has beenexplained with reference especially to FIG. 6.

As is apparent from the above description, the moditied honing head ofFIGS. 7 and 8 employs the damping reservoir 119 in which air and oil areconfined under pressure. Air is known to be more compressible than oil,so that the coexistance of the two in the reservoir 119 will highly dampor absorb such a shock, if any, as is often experienced at the contactinterface between the workpiece inner periphery and the stone slips 113.

Reverting to FIG. 7, the connection of the honinghead proper 106 to thespindle 102 is performed in a manner that the former is receivedvertically slidably in but is made to rotate integrally with the latter.For this purpose, guide tube 132 is fastened to the head proper 106 atits radially outer portion by'a suitable screw (not numbered). Into thecentral bore of the guide tube 132 is slidably inserted a guide pin 131which is screwed into the spindle 102. Thus, in operation, the headproper 106 can rotate together with the spindle 102 by the rotationalmotion transmitted through the gear 104. At the same time, the slidingcontact between the guide tube 132 and the guide pin 131 will permit thehead proper 106 to vertically move with a considerable stroke, whenvertical positioning of the honing head is effected into and out of theworkpiece bore, and with a limited amplitude when vertical oscillationsare applied to the head proper 106 through the vibration rod 107, bothindependently of the spindle 102.

It should be appreciated here that the honing machine according to thepresent invention is featured by finishing a complicated trochoidal boreof a rotor housing of a rotary engine at a high speed According to theinvention, eccentricity between the centers of the honing head and theworkpiece, which is known to affect the resultant trochoidal form, canbe adjusted to make the honing head follow smoothly and finely theobtained trochoidal inner surface.

According to the invention, moreover, the bias pressure of the stoneslips against the workpiece inner surface can be periodically reducedand increased in response to the angular positions of the slips, so thatthe bias pressure is uniformly obtained even when the slips face thereduced portion with a hole such as an exhaust port of the rotorhousing.

Still moreover, shocks as experienced at the contact interfaces betweenthe workpiece inner surface and the acting surfaces of the stone slipsare pneumatically damped or absorbed to obviate damage of the workpieceinner surfacebeing finished.

What is claimed is:

l. A honing machine for finishing a trochoidal bore of a workpiece byhoning the inner wall surface thereof, comprising:

a relatively stationary main body;

a drive shaft rotatably born on said main body and provided with twointegral gears;

a honing head provided on its periphery with a plurality of stone slipswhich are biased outwardly into sliding contact with the inner wallsurface of the workpiece for honing the same when rotatably receivedwithin the trochoidal bore;

a cylindrical shaft having its axis arranged in parallel a firstintermediate idle gear meshing with one of the gears of said drive shaftand with the gear of said cylindrical shaft for transmitting rotationalmotion from said drive shaft to said honing head by way of saidcylindrical shaft and honing-head shaft; machine table for holding theworkpiece in position;

table shaft coaxially secured to said machine table and provided with anintegral gear, said table shaft having its axis arranged eccentricallyof the axis of said honing-head shaft but in parallel with the axis ofsaid drive shaft;

second intermediate idle gear meshing with the other gear of said driveshaft and with the gear of said table shaft for transmitting rotationalmotion from said drive shaft to said machine table by way of said tableshaft, the direction of rotation of said honing head being the same asthat of said machine table, and the ratio of speed of rotation of theformer to that of the latter being predetermined, so that the formermoves relative to the latter in a manner to draw a preset trochoidalcurve; and

eccentricity control means for finely controlling eccentricity betweenthe axes of said honing head shaft and table shaft.

2. A honing machine according to claim 1, further comprising:

head-position control means connected to said honing-head shaft forhydraulically moving said honing head along the axis thereof in a firstposition, at which the stone slips of said honing head are in slidingcontact with the inner wall of said trochoidal bore, and into a secondposition, at which said honing head is apart from said trochoidal borein a standby position; and

locking means for locking said head-position control means to hold saidhoning head at the second position.

3. A honing machine according to claim 1, wherein said eccentricitycontrol means includes a bolt threaded into said stationary main bodyand adapted to be turned for dislocating said table shaft relative tosaid honing-head shaft.

4. A honing machine according to claim 1 which further comprises meansfor moving the second intermediate idle gear with respect the other gearof said drive shaft with the clearance between the other gear of saiddrive shaft and the second intermediate idle gear maintainedsubstantially constant.

5. A honing machine for finishing a trochoidal bore of a workpiece byhoning the inner wall surface thereof, comprising:

a relatively stationary main body;

a drive shaft rotatably born on said main body and provided with twointegral gears;

a honing head provided on its periphery with a plurality of stone slipswhich are biased outwardly into sliding contact with the inner wallsurface of the workpiece for-honing the same when rotatably receivedwithin the trochoidal bore;

a cylindrical shaft having its axis arranged in parallel with the axisof said drive shaft and provided with an integral gear;

a honing-head shaft coaxially secured to said honing head and coaxiallyreceived in said cylindrical shaft, said honing-head shaft being axiallymovable within said cylindrical shaft for bringing said honing head intoand out of the trochoidal bore but being forced to rotate integrallywith said cylindrical shaft; a first intermediate idle gear meshing withone of the gears of said drive shaft and with the gear of saidcylindrical shaft for transmitting rotational motion from said driveshaft to said honing head by way of said cylindrical shaft andhoninghead shaft; a machine table for holding the workpiece in position;a table shaft coaxially secured to said machine table and.provided withan integral gear, said table shaft having its axis arrangedeccentrically of the axis of said honing-head shaft but in parallel withthe axis of said drive shaft;

a second intermediate idle gear meshing with the other gear of saiddrive shaft and with the gear of said table shaft for transmittingrotational motion from said drive shaft to said machine table by way ofsaid table shaft, the direction of rotation of said honing head beingthe same as that of said machine table, and the ratio of speed ofrotation of the former to that of the latter being predetermined, so

that the former moves relative to the latter in a manner to draw apreset trochoidal curve;

eccentricity control means for finely controlling eccentricity betweenthe axes of said honing head shaft and said table shaft;

detecting means responsive to the rotational motion of said honing headrelative to said machine table for detecting the angular positions ofthe stone slips of said honing head relative to the inner wall surfaceof the trochoidal bore;

bias-pressure control means for controlling the bias pressure of saidstone slips toward said inner wall surface;

a pressurized fluid source communicating with said bias-pressure controlmeans for supplying thereto a liquid under pressure; and

change-over means provided between said biaspressure control means andsaid pressurized fluid source and responsive to the relative angularpositions of said stone slips for changing the communication of saidpressurized fluid source with said bias-pressure control means,

whereby the bias pressure of said stone slips are controlled independence upon the relative angular positions of said stone slips.

6. A honing machine according to claim 5, further comprising pneumaticdamping means provided between said change-over means and saidbias-pressure control means and including an air chamber forpneumatically damping the bias pressure of said stone slips irrespectiveof the variation of said bias pressure.

1. A honing machine for finishing a trochoidal bore of a workpiece byhoning the inner wall surface thereof, comprising: a relativelystationary main body; a drive shaft rotatably born on said main body andprovided with two integral gears; a honing head provided on itsperiphery with a plurality of stone slips which are biased outwardlyinto sliding contact with the inner wall surface of the workpiece forhoning the same when rotatably received within the trochoidal bore; acylindrical shaft having its axis arranged in parallel with the axis ofsaid drive shaft and provided with an integral gear; a honing-head shaftcoaxially secured to said honing head and coaxially received in saidcylindrical shaft, said honing-head shaft being axially movable withinsaid cylindrical shaft for bringing said honing head into and out of thetrochoidal bore but being forced to rotate integrally with saidcylindrical shaft; a first intermediate idle gear meshing with one ofthe gears of said drive shaft and with the gear of said cylindricalshaft for transmitting rOtational motion from said drive shaft to saidhoning head by way of said cylindrical shaft and honinghead shaft; amachine table for holding the workpiece in position; a table shaftcoaxially secured to said machine table and provided with an integralgear, said table shaft having its axis arranged eccentrically of theaxis of said honing-head shaft but in parallel with the axis of saiddrive shaft; a second intermediate idle gear meshing with the other gearof said drive shaft and with the gear of said table shaft fortransmitting rotational motion from said drive shaft to said machinetable by way of said table shaft, the direction of rotation of saidhoning head being the same as that of said machine table, and the ratioof speed of rotation of the former to that of the latter beingpredetermined, so that the former moves relative to the latter in amanner to draw a preset trochoidal curve; and eccentricity control meansfor finely controlling eccentricity between the axes of said honing headshaft and table shaft.
 2. A honing machine according to claim 1, furthercomprising: head-position control means connected to said honing-headshaft for hydraulically moving said honing head along the axis thereofin a first position, at which the stone slips of said honing head are insliding contact with the inner wall of said trochoidal bore, and into asecond position, at which said honing head is apart from said trochoidalbore in a standby position; and locking means for locking saidhead-position control means to hold said honing head at the secondposition.
 3. A honing machine according to claim 1, wherein saideccentricity control means includes a bolt threaded into said stationarymain body and adapted to be turned for dislocating said table shaftrelative to said honing-head shaft.
 4. A honing machine according toclaim 1 which further comprises means for moving the second intermediateidle gear with respect the other gear of said drive shaft with theclearance between the other gear of said drive shaft and the secondintermediate idle gear maintained substantially constant.
 5. A honingmachine for finishing a trochoidal bore of a workpiece by honing theinner wall surface thereof, comprising: a relatively stationary mainbody; a drive shaft rotatably born on said main body and provided withtwo integral gears; a honing head provided on its periphery with aplurality of stone slips which are biased outwardly into sliding contactwith the inner wall surface of the workpiece for honing the same whenrotatably received within the trochoidal bore; a cylindrical shafthaving its axis arranged in parallel with the axis of said drive shaftand provided with an integral gear; a honing-head shaft coaxiallysecured to said honing head and coaxially received in said cylindricalshaft, said honing-head shaft being axially movable within saidcylindrical shaft for bringing said honing head into and out of thetrochoidal bore but being forced to rotate integrally with saidcylindrical shaft; a first intermediate idle gear meshing with one ofthe gears of said drive shaft and with the gear of said cylindricalshaft for transmitting rotational motion from said drive shaft to saidhoning head by way of said cylindrical shaft and honing-head shaft; amachine table for holding the workpiece in position; a table shaftcoaxially secured to said machine table and provided with an integralgear, said table shaft having its axis arranged eccentrically of theaxis of said honing-head shaft but in parallel with the axis of saiddrive shaft; a second intermediate idle gear meshing with the other gearof said drive shaft and with the gear of said table shaft fortransmitting rotational motion from said drive shaft to said machinetable by way of said table shaft, the direction of rotation of saidhoning head being the same as that of said machine table, and the ratioof speed of rotation of the former to that of the latter beinGpredetermined, so that the former moves relative to the latter in amanner to draw a preset trochoidal curve; eccentricity control means forfinely controlling eccentricity between the axes of said honing headshaft and said table shaft; detecting means responsive to the rotationalmotion of said honing head relative to said machine table for detectingthe angular positions of the stone slips of said honing head relative tothe inner wall surface of the trochoidal bore; bias-pressure controlmeans for controlling the bias pressure of said stone slips toward saidinner wall surface; a pressurized fluid source communicating with saidbias-pressure control means for supplying thereto a liquid underpressure; and change-over means provided between said bias-pressurecontrol means and said pressurized fluid source and responsive to therelative angular positions of said stone slips for changing thecommunication of said pressurized fluid source with said bias-pressurecontrol means, whereby the bias pressure of said stone slips arecontrolled in dependence upon the relative angular positions of saidstone slips.
 6. A honing machine according to claim 5, furthercomprising pneumatic damping means provided between said change-overmeans and said bias-pressure control means and including an air chamberfor pneumatically damping the bias pressure of said stone slipsirrespective of the variation of said bias pressure.